Device and method for treatment of spinal deformity

ABSTRACT

The present invention generally relates to methods and device for treatment of spinal deformity, wherein at least one tether is utilized to maintain the distance between the spine and the an ilium to (1) prevent increase in abnormal spinal curvature, (2) slow progression of abnormal curvature, and/or (3) impose at least one corrective displacement and/or rotation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.14/930,800, filed on Nov. 13, 2015, which is a continuation-in-part ofU.S. application Ser. No. 14/039,660, filed Sep. 27, 2013, now U.S. Pat.No. 9,757,160, which claims priority to U.S. Provisional ApplicationSer. No. 61/744,525 filed on Sep. 28, 2012, the contents of which arehereby incorporated by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to methods and devices fortreatment of spinal deformity.

BACKGROUND OF THE INVENTION

Scoliosis is a spinal deformity characterized by an abnormal curvatureof the spine in the coronal plane. Adolescent idiopathic scoliosis (AIS)is the most prevalent type of scoliosis which develops duringadolescence in an otherwise healthy patient and typically ceases at theonset of skeletal maturity. The cause of the disease is presentlyunknown.

Current surgical treatment of scoliosis involves manipulation of thespinal column and attachment of corrective devices for fusion of aportion of the spine. One such system, the Cotel-Dubousset systemutilizes rigid metal rods attached to the spine. The rods aremanipulated during surgery in an attempt to reduce abnormal curvaturesand rotations of the spinal column. Large loads are exerted on the spinefor correction which risks the patient's neurological condition.Recovery from these procedures can be lengthy and painful. Also, ifnormal lordosis and kyphosis are not restored, a condition called “flatback syndrome” may occur causing chronic pain. Even a successfulprocedure rarely results in a normal spinal curvature and the patient isleft with an immobile spinal section. The discs above and below thefusion zone are at risk of future degeneration due to the increasedmechanical demands placed on them.

It is therefore evident that there are flaws in prior art methods anddevices. Most prior art devices are part of the load path of the spinalcolumn. For example, it is understood that the Cotel-Dubgousset systemrigidly attaches stiff metal rods to the spine. A structure having tworoughly parallel support members relies primarily on the stiffer of thetwo members for transmission of loads. Therefore, loads exerted on aninstrumented spine are transferred through the implant instead ofthrough the spine. Spinal loads can be significantly large, and theimplants will not support such loads indefinitely. Fatigue failure ofthe implant will occur if fusion is delayed.

Therefore, there is an unaddressed need that exists to provide a new andbetter system for correcting spinal deformities.

SUMMARY OF THE INVENTION

The current invention describes methods and devices for treating spinaldeformity which offer significant improvements over prior art methodsand devices. In general terms the present invention is used to securethe distance between an ilium and the spine to either correct ormaintain spinal curvature. There are many embodiments of the inventionwhich will achieve the stated objectives, some of which will bepresented in the following summary.

In one embodiment of the invention, at least one device is attachedbetween the spine and the pelvis which incorporates at least oneflexible tether. Attachment of the flexible tether to the spine andilium involves implantation of anchoring means and then attachment ofthe tether to the anchoring means. For example, at least one bone screw,pedicle screw, cannulated bone screw, clamp, plate, bone anchor, orshackle might be anchored to at least one vertebra and another to aportion of the ilium and the flexible tether may be attached to both.Other means of attachment will be clear to one practiced in the art.Alternatively, a loop of material may be placed around a bony structure(e.g. spinous process, transverse process, lamina or pars) or a holethrough a bony structure through which the flexible tether is passed.

It should be noted that the present invention enables manipulating thevertebral column to correct the deformity by securing the tether to aportion of the ilium and a portion of the vertebral column; the abilityto correct deformity by correcting the effective length of the tetherbetween the ilium and vertebra over time; and correcting deformity bythe natural growth of the spine by allowing the tether to maintaineffective length between the vertebral column and the ilium.

Adjustment of the distance between the spine and ilium is achieved byvarying the location at which the tether is attached to the anchoringmeans. The tether does not change lengths during the adjustment process,but the distance between the attachment points does, much like adjustinga belt around your waist. Taking advantage of the inherentviscoelasticity of spinal structures, the curvature may be graduallycorrected by small incremental corrections over a protracted period oftime, whereby the original incision is re-opened, or a new incision nextto the original incision is created and the attachment means isdisengage and then reengaged at a different location along the tether.Alternatively the patient's growth may be used to achieve correction.

Alternatively, the tether may branch into multiple tethers to providemultiple attachments to the spine and/or ilium. If more than one tetheris used, each can be attached to a different vertebra, or multipletethers can be attached to the same vertebra. Tethers can be attached toeither or both sides of the vertebral column and either opposing sidesof ilium as needed to generate correction of the spinal deformity. Acrossing pattern whereby a tether is attached to the right side of thevertebra (e.g. the right pedicle) and left ilia, or vice versa, ispossible. Also, a tether may be attached to a vertebra and then passedthrough an eye screw or other guiding device which is attached to theilium (or both ilia) and then attached to a second vertebra with apedicle screw or other means. In can be envisioned by one skilled in theart that guiding devices may be utilized on a number of vertebrae or onethe ilium or ilia. The tether may also originate with an attachment tothe pelvis, pass through any number of guide members attached to thespine, and then terminate at the pelvis again.

According to another embodiment, a spinal system for correcting adeformity in the spine includes a tether, an anchor, an elongate rod andtwo bone fasteners, a clamp, and a fastener. The clamp is securable tothe elongate rod. The clamp includes a clamp body and a hasp bodyhingedly connected to the clamp body. The clamp body has a first openingextending through the clamp body, and the hasp body has a second openingextending through the hasp body. When the clamp is closed, the first andsecond openings are aligned with one another, and the fastener isconfigured to be received through the first and second openings tosecurely lock the tether within the clamp. The hasp body may include ahinge sleeve portion having an opening extending therethrough, and apivot pin received in the opening and connected to the clamp body toallow for pivotal movement of the hasp body relative to the clamp body.The tether may be temporarily secured to the clamp body, before theclamp is closed, by first and second elongate slots extending throughthe clamp body, which are configured to receive the tether.Alternatively, the clamp body may include an elongate pin member withopposing ends configured to be received in the clamp body so that thetether wraps around the elongate pin to temporarily secure the tether inthe clamp.

These and other aspects of the present invention will become apparentfrom the following description of the embodiments taken in conjunctionwith the following drawings, although variations and modificationstherein may be affected without departing from the spirit and scope ofthe novel concepts of the disclosure.

The present invention provides an improved method of arresting a spinaldeformity whereby at least one device is surgically attached between thespine and the ilium. Also, the present invention provides a system and amethod for correcting a spinal deformity whereby at least one device issurgically attached between the spine and the ilium. One method ofadjusting the curvature of the spine without fusion may include, forexample, installing an anchor into a portion of the ilium; installingtwo bone fasteners into the pedicles of a vertebra and connecting anelongate rod between the two bone fasteners; attaching a first end of atether to the anchor; attaching a second end of the tether to a clamp,the clamp having a clamp body and a hasp body hingedly connected to theclamp body, the clamp body having a first opening extending through theclamp body, and the hasp body having a second opening extending throughthe hasp body; closing the clamp such that the first and second openingsare aligned with one another; inserting a fastener through the first andsecond openings to securely lock the tether within the clamp; andconnecting the clamp to the elongate rod. Another method of adjustingthe curvature of the spine without fusion may include axially rotatingone or more vertebra to produce a lateral shift in the spine.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an illustration of a posterior view of a deformed human spinewith an implanted device according to one embodiment of the presentinvention;

FIG. 2 is an illustration of a posterior view of a corrected human spinewith the implanted device shown in FIG. 1;

FIG. 3 shows a spinal anchoring means in the form of two pedicle screwsand a rod onto which is secure an attachment mechanism and the tether;

FIG. 4 illustrates an attachment mechanism and the method of attachingit to the spinal anchoring mechanism;

FIG. 5 shows the anchoring mechanism of the ilium (not shown) and themethod of attaching the tether to it;

FIG. 6 shows a long pair of forceps to be used for passing the tetherbeneath the skin;

FIG. 7 illustrates the use of the forceps of FIG. 6 in passing thetether beneath the skin;

FIG. 8 illustrates an alternative embodiment of the tether clamp andelongate rod according to the present invention;

FIG. 9 illustrates another embodiment of a clamp or anchor according tothe present invention;

FIG. 10 shows a cross-sectional view of the device shown in FIG. 9;

FIG. 11 shows another embodiment of a clamp or anchor according to thepresent invention;

FIGS. 12 and 13 shows a closed head clamp according to the presentinvention;

FIGS. 14 and 15 shows yet another embodiment of a closed head clampaccording to the present invention;

FIGS. 16-18 illustrate various methods of coupling the tether toportions of the spine and/or ilium;

FIGS. 19-21 illustrate an alternative embodiment of a tether clamp;

FIGS. 22 and 23 provide yet another alternative for a tether clamp;

FIGS. 24 and 25 depict a posterior view of a deformed human spine and acorrected human spine, respectively, with an implanted device accordingto one embodiment;

FIGS. 26 and 27 show a method and device for correcting scoliosis byde-rotating the vertebra in the axial plane; and

FIG. 28 depicts an alternative version of coupling the tether to thespine by looping the tether around the lamina.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses. The invention being thus described, it will beobvious that the same may be varied in many ways. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention, and all such modifications as would be obvious to one skilledin the art are intended to be included within the scope of the followingclaims.

FIG. 1 is an illustration of a posterior view of a deformed spine 104whereby the preferred embodiment of the device 200 is attached to anilium 102 and a vertebra 100. Device 200 includes a tether 204 having afree end 206 and that is configured to be attached to the ilium and aportion of the vertebra. Specifically, in one embodiment, two attachmentmechanisms such as pedicle screws 300 are anchored to the vertebra ofthe spine by insertion into opposing pedicles, and a transverse rod 311is attached to the pedicle screws 300. It should be noted that althoughpedicle screws are provided in this particular embodiment, any othertype of anchoring mechanism such as hooks may also be used. A tetherclamp 310 is attached to rod 311 and the tether 204 is passed throughtether clamp 310 and then passed down to the ilium 102 thereby securinga connection between the attached vertebra and the ilium. To attach thetether 204 to the ilium 102, an ilium anchor 210 is provided. The iliumanchor 210 includes a bore 211 and is configured to be attached to theilium by inserting the anchor 210 (threading) into a hole which has beendrilled or punched through the ilium 102. It should be noted that anyother similar mechanism to attach anchor 210 to the ilium 102 may alsobe utilized. Tether 204 is passed through hole or bore 211 in the iliumanchor 210 and then brought back to the vertebra 100 and passed againthrough the tether clamp 310. In other embodiments, the tether 204 mayonly be passed once through the tether clamp and ilium anchor 210.

FIG. 2 illustrates the correction of the spine of FIG. 1 using device200. As illustrated in FIG. 2, the free end 206 of tether 204 is pulledand the spine is manually manipulated during the surgery to achieve acorrection of the deformity. When a satisfactory curve magnitude isachieved, tether 204 is tightened within the tether clamp, effectivelylocking the distance between vertebra 100 and the ilium 102.

It should be noted that various levels of manipulation of the vertebralcolumn can be coordinated using the device. For instance, differentcurvatures of the spine can be achieved by changing the position of theanchor and the clamp on the tether with respect to the vertebral columnand the ilium. The locations along the tether where the clamp and anchorare attached determine an effective length of the tether, which in turnmaximizes the distance that the attached vertebra may move relative tothe position where the tether is attached at in the ilium. The scolioticcurve is corrected (or maintained) by adjusting the clamping andanchoring locations along the tether.

FIG. 3 shows a detailed view of pedicle screws 300, transverse rod 311,tether clamp 310 and tether 204. In a preferred embodiment tether clamp310 includes locking screw 312 which clamps tether clamp 310 onto rod311 as well as locking the tether 204 within the clamp 310.

FIG. 4 shows a detailed view of the tether clamp 310 coupled to thetransverse rod. The tether clamp 310 is configured with a slot 501 whichis provided through the tether clamp 310 and tether 204 is passedthrough slot 501. It should be noted that the tether may be passedthrough the slot multiple times, if necessary. Locking screw 312 is usedto secure the transverse rod 311 onto the tether clamp 310 and applies acompressive force upon the rod 311 onto the tether 204, thereby clampingthe tether 204 securely in place. It should be noted that although athreaded set screw is utilized in the present embodiment, any type oflocking element know in the art for securing the tether within tetherclamp may be used.

FIG. 5 shows a detailed view of an ilium anchor 210. Ilium anchor 210includes threads 212 for engagement with ilium 102 (not shown). Tether204 is passed through bore 211 and then passed back to the vertebralcolumn. A collar 215 is shown which keeps tether 204 adjacent to itself.

FIG. 6 shows an extra-long pair of forceps 900. FIG. 7 shows thepreferred method of passing the tether through an incision 845 andunderneath skin and other soft tissues. The forceps 900 are used to passthe tether through the openings in the tether clamp and used to tensionthe tether to correct the deformity of the curvature in the spine.

FIG. 8 illustrates another embodiment of a tether clamp 320 according tothe present invention. In this embodiment, the tether clamp 320 isconfigured with a through hole 322 that is configured to correspond to athrough hole 324 in an elongate rod 326 that is fixated to a portion ofthe spinal column. A fastening element 328 such as a set screw isprovided to couple the tether clamp 320 and the elongate rod 326together. The tether clamp 320 also includes openings 330, 332 which aredimensioned to receive and securely couple a tether 334 to the clamp320. The tether 334 is pulled through each of the openings 330, 332 tosecurely attach the tether 334 to the clamp 320 and the elongate rod326.

FIGS. 9 and 10 illustrate an alternative embodiment of a clamp and/oranchor 250 that can be used to secure a tether 252 to either thevertebral column or a portion of the ilium. More specifically, theanchor 250 of FIGS. 9 and 10 may be configured and dimensioned to beattached to a portion of the vertebral column or may be configured besecure the tether to the ilium. The anchor 250 is configured as a plate251 having at least two openings 254, 256 to receive fasteners 258, 260capable of fixating the plate to bone. The plate 251 includes a middleportion 262 having an opening 264 that is capable of receiving thetether 252. The middle portion 262 of the plate 251 is further providedwith a fastening element 266 to secure the tether 252 to the plate 251.As more clearly illustrated in FIG. 10, the fastening element 266 may bea set screw which directly contacts the tether 252 when tightened tosecure the tether 252 to the plate 251. It should be noted that anyother type of fastening element which is capable of securing the tetherto the anchor may be used, such as a pin.

FIG. 11 illustrates yet another embodiment of a clamp or anchor 400according the present invention. In this embodiment, the clamp and/oranchor 400 includes a first plate 402 and second plate 404 that aresecured to one another via a fastening element 406. The first and secondplates 402, 404 are may also include spikes 408 or similar type offeatures that bite into bone. Either the first or second plate 402, 404or both also includes an opening 410 for receiving a tether. The firstand second plates 402, 404 are positioned so that bone is in between,such as the ilium or a portion of the vertebral column. As the first andsecond plates 402, 404 are compressed into bone, the tether which ispositioned through the opening 410 and in between the first and secondplates 402, 404, is also securely locked between the plates and the bonethereby securing the tether to the plates 402, 404. In an alternativeembodiment, the tether is passed through the opening and secured to theanchor 400 by a clamp device such a belt clamp or secured by knottingthe tether around the edge of the anchor 400. It should be noted thatany type of mechanical mechanism to attach the tether to the anchor maybe used.

FIGS. 12-15 illustrate yet another embodiment of a clamp according tothe present invention. The closed head clamp 420, as illustrated inFIGS. 12 and 13, includes a first opening 422 extending through theclamp 420 in a first direction and a second opening 424 extending in asecond direction. The first and second directions are generallyperpendicular to one another. The first opening 422 is configured toreceive an elongate rod 426 and the second opening 424 is configured toreceive a tether 428. The clamp 420 is further provided with a fasteningelement 430 that is used to secure both the rod 426 and the tether 428.In this embodiment, FIGS. 12 and 13 also illustrates that the secondopening 424 is positioned at a bottom portion of the clamp 420, thus, asthe fastening element 430 is tightened, the fastening element 430contacts the rod 426 which is pushed against the tether 428 therebysecuring the tether 428 and rod 426 within the clamp.

In an alternative embodiment of the closed head clamp as illustrated inFIGS. 14 and 15, the closed head clamp 432 includes a first opening 434and a second opening 436. The first opening 434 and the second opening436 are configured to be generally transverse to one another. The firstopening 434 is dimensioned to receive an elongate rod 438 and the secondopening 436 is dimensioned to receive a tether 440. The clamp 432 alsoincludes a fastening element 442, such as a set screw, which whentightened secures and locks the tether 440 and the elongate rod 438within the clamp 432. In this particular embodiment, the second opening436 is positioned between the fastening element 442 and the elongate rod438. When the fastening element 442 is tightened, the fastening element442 directly contacts the tether 440 which contacts the elongate rod 438thereby securely locking the tether 440 and the elongate rod 438 withinthe closed head clamp 432.

FIGS. 16-18 illustrate alternative embodiments of the inventive device.Specifically, FIG. 16 illustrates the use of clamp to attach the tetherto the lamina of a vertebra. As illustrated, the tether may encircle thelamina and may be tightened using a belt clamp. In an alternativeversion shown in FIG. 28, the tether 204 may be looped around the lamina106 and a force F applied to the tether 204. The other end of the tetheris as shown in the earlier embodiments coupled to a portion of theilium. Using this mechanism, the deformity of the spine may be correctedby manipulating the tether as well as the positioning of the clamp, asneeded.

FIG. 17 shows a tether that includes a loop which is used to forcoupling the tether to the transverse rod to fixate the tether to thetransverse rod. FIG. 18 illustrates the coupling of the tether directlyto the ilium using another type of tether clamp. It should be noted thatin the examples provided of both anchor and clamps, these mechanicaldevices may be interchangeable.

It should also be noted that the tether of the present invention may becomposed of fabric, polymer, such as PET, or any other biocompatiblematerials. The tether can be a cable and can be dimensioned to be a wideelastic band which advantageously reduce the risk of damage to tissuelacerations or injury. In some embodiments, the tether can be is between2 and 900 mm. Also, to ensure that proper correction of deformities, atensioner can be included as part of the system to make sure that thetether is in proper tension and tightness.

FIGS. 19-21 show an alternative version of a tether clamp 520. Similarto tether clamp 320, tether clamp 520 is configured to couple a tether204 to an elongate rod 326. FIG. 19 shows the clamp 520 in an openconfiguration. FIG. 20 shows the clamp 520 in a closed configurationwith a fastener 528. FIG. 21 depicts the clamp 520 attached to anelongate rod 326 with fastener 528. The tether clamp 520 is in the formof a hinged clamp configured to clamp the tether 204 and connect thetether 204 to the rod 326. The hinged tether clamp 520 includes a mainclamp body 524, a hasp body 526 hingedly connected to the clamp body524, and a fastener 528 (such as a screw) configured to secure the haspbody 526 to the clamp body 524 and the clamp 520 to the elongate rod326. The hasp body 526 is able to pivotally move with respect to theclamp body 524 to allow for the open and closed configurations.

The clamp body 524 may extend from a distal end to a proximal end. Theclamp body 524 may include a through hole 522 extending through theclamp body 524. The through hole 522 may be positioned closer to thedistal end of the clamp body 524. The through hole 522 may by generallyspherical in cross-section and sized and dimensioned to receive at leasta portion of the fastener 528. The inner surface of the through hole 522may be non-threaded or threaded. Preferably, the inner surface of thethrough hole 522 is threaded to mate with corresponding threads on thefastener 528.

The clamp body 524 further includes a first elongate opening 530extending through the clamp body 524 and a second elongate opening 532extending through the clamp body 524. The second elongate opening 532may be positioned closer to the proximal end of the clamp body 524, andthe first elongate opening 530 may be positioned between the throughhole 522 and the second elongate opening 532. The first elongate opening530 may be separate and distinct from the through hole 522, as shown inthe embodiment FIG. 19, or may join to form a single irregular opening,as shown in the embodiment in FIG. 22. The second elongate opening 532may be defined by the clamp body 524 or the second elongate opening 532may be created by the hinge of the clamp 520. The first and secondelongate openings 530, 532 may be substantially parallel to one another.The first and second elongate openings 530, 532 are preferably sized anddimensioned to receive the corresponding width and thickness of thetether 204. Thus, the tether 204 is configured to be received by andthrough the first and second elongate openings 530, 532 in any suitableconfiguration to at least temporarily hold the tether 204 in the clampbody 524.

A preferred way of threading the tether 204 to the clamp body 524 isshown in FIG. 19 by arrow A. As shown by arrow A, a free end 206 of thetether 204 is passed through the first elongate opening 530 in the clampbody 524 and back through the second elongate 532 such that the tether204 substantially folds back onto itself. When the tether 204 is passedthrough the clamp body 524 (as shown by arrow A), the clamp 520 willtemporarily hold the position of the tether 204 when the tether 204 istensioned. Thus, the tether 204 may be appropriately tensioned bypulling on the free end 204 of the tether 204 and advancing the tether204 through the first and second elongate openings 530, 532. Similarly,the tension may be reduced by allowing the tether 204 to retract backthrough the first and second elongate openings 530, 532.

Once the tether 204 is appropriately tensioned, the hasp body 526 may beclosed into contact with or close into contact with the clamp body 524.The hasp body 526 also extends from a distal end to a proximal end. Thedistal end of the hasp body 526 forms a hinge sleeve portion 534. Thehinge sleeve portion 534 may have an opening extending longitudinallytherethrough sized and configured to receive a pivot pin 536. Theopposing ends of the pivot pin 536 are each configured to be received inand engage one or more openings extending through the clamp body 524.Thus, the pivot pin 536 enables the hasp body 526 to pivot or angulatewith respect to the clamp body 524. For example, the hasp body 526 maybe positioned at an angle ranging from about 45-180°, about 50-120°,about 60-110°, about 70-100°, or about 90° relative to the clamp body524, when in an opened position.

The hasp body 526 includes a through hole 538 extending through the haspbody 526. The through hole 538 may be positioned closer to the distalend of the hasp body 526. The through hole 538 may by generallyspherical in cross-section and sized and dimensioned to receive at leasta portion of the fastener 528. The inner surface of the through hole 538may be non-threaded or threaded. When the hasp body 526 is aligned withthe clamp body 524, the through hole 538 of the hasp body 526 alignswith the through hole 522 of clamp body 524. As shown in FIG. 20, whenthe through holes 522, 538 are aligned, fastener 528 may be insertedtherethrough to lock the tether 204 to the clamp 520. The through hole538 of the hasp body 526 may be substantially the same size or largerthan the through hole 522 of clamp body 524. The through hole 538 ispreferably sized larger to receive a head portion 540 of the fastener528 when recessed into the hasp body 526.

Referring to FIG. 21, the fastener 528 is attachable to the clamp 520and the rod 326 in order to compress the tether 204 between the haspbody 526 and the clamp body 524, thereby providing a more substantial,permanent hold. The fastener 528 may include a head portion 540 and ashaft portion extending therefrom. The head portion 540 may include arecess sized and configured to receive a driving instrument, such as ahex driver, in order to rotate and insert the fastener 528 through thethrough holes 538, 522 and into an opening 324 in the elongate rod 326.Thus, the fastener 528, when tightened, causes the hasp body 526including the hinge sleeve portion 534, which may be enlarged relativeto the rest of the hasp body 526, to squeeze the tether 204 between theclamp body 524 and the hasp body 526 and/or hinge sleeve portion 534 topermanently secure the tether 204 in position. The hinge sleeve portion534 is preferably sized and dimensioned to apply an appropriate force tothe tether 204 to secure the tether to the clamp 520. As shown, thehinge sleeve portion 534 may have a generally cylindrical or partiallyspherical shape, which is enlarged relative to the rest of the hasp body526, to further tighten the tether 204 when the hasp body 526 is rotatedto the closed position.

Referring now to FIGS. 22 and 23, another version of a tether clamp 620,in the form of a hinged clamp, configured to clamp the tether 204 withthe clamp 620 is shown. Similar to tether clamp 520, the hinged tetherclamp 620 includes a main clamp body 624, a hasp body 526 hingedlyconnected to the clamp body 624, and a fastener 628 configured to securethe hasp body 626 to the clamp body 624 and the clamp 620 to theelongate rod 326. FIG. 22 shows the clamp 620 in an open configuration,and FIG. 23 shows an exploded view of the clamp 620, elongate rod 326,and fastener 628.

As shown in FIG. 22, the clamp body 624 may have a generally U-shapedbody. The clamp body 524 may include a through hole 622 extendingthrough the clamp body 624. The through hole 622 may have apartial-spherical cross-section and sized and dimensioned to receive atleast a portion of the fastener 528. The inner surface of the throughhole 622 may be threaded to mate with corresponding threads on thefastener 628. The clamp body 624 further includes an enlarged opening630 extending through the clamp body 624. The enlarged opening 630 andthrough hole 622 may join to form a single irregular opening (e.g., akey-shaped opening defined by the outer U-shaped clamp body 624). Anelongate pin member 642 may connect a first side to a second side of theU-shaped clamp body portion 624. In particular, opposing ends of the pinmember 642 are each configured to be received in and engage one or moreopenings extending through the clamp body 624. The tether 204 isconfigured to be received around the elongate pin member 642 in anysuitable configuration to at least temporarily hold the tether 204 inthe clamp body 624. The tether 204 may be looped around the pin member642 and in direct contact with the pin member 642 for temporaryattachment.

Similar to the threading of the tether 204 shown in FIG. 19, a free end206 of the tether 204 may be passed through the space between thethrough hole 622 and the pin member 642 in the clamp body 624 and backthrough the space between the pin member 642 and the hinge sleeveportion 634 such that the tether 204 substantially folds back ontoitself. The clamp 620 will temporarily hold the position of the tether204 as the tether 204 is appropriately tensioned to correct the spinaldeformity.

The hasp body 626 includes a through hole 638 extending through the haspbody 626. When the hasp body 626 is aligned with the clamp body 624, thethrough hole 638 of the hasp body 626 aligns with the through hole 622of clamp body 624 and fastener 628 may be inserted therethrough to lockthe tether 204 to the clamp 620. Once the tether 204 is appropriatelytensioned, the hasp body 626 may be closed into contact with or closeinto contact with the clamp body 624. The distal end of the hasp body626 forms an enlarged hinge sleeve portion 634 including an openingextending longitudinally therethrough sized and configured to receive apivot pin 636. The opposing ends of the pivot pin 636 are eachconfigured to be received in and engage one or more openings extendingthrough the clamp body 624. Thus, the pivot pin 636 enables the haspbody 626 to pivot or angulate relative to the clamp body 624 and allowsfor open and closed configurations of the clamp 620.

The fastener 628 may include a head portion 640 and a shaft portionextending therefrom. A portion of the shaft portion may be threaded, asshown in FIG. 23. The shaft portion may be threaded along the entirelength or any suitable portion thereof. Preferably, at least the portionof the shaft in contact with the through hole 622 in the clamp body 624and the opening 324 in the elongate rod 326 is threaded. The headportion 540 may include a recess sized and configured to receive adriving instrument, such as a hex driver, in order to rotate and insertthe fastener 628 through the through holes 638, 622 and into an opening624 in the elongate rod 626.

As best seen in FIG. 23, the elongate rod 626 and clamp 620 may furtherinclude a clutch feature in the form of radial grooves 325 andcorresponding radial grooves (not visible) on the back of the clamp 620so that no counter-torque instrument is needed to prevent rotation ofthe clamp 620 during tightening of the fastener 628. The radial grooves325 may be in the form of radial slots, protrusions, or the likeextending around the opening 324 in the elongate rod 326. Thecorresponding radial grooves include mating radial slots, protrusions,or the like extending around the opening 622 in the clamp body 624. Thefastener 628 is attachable to the clamp 620 and the rod 626 in order tocompress the tether 604 between the hasp body 626 and the clamp body624, thereby providing a more substantial, permanent hold. Thus, thefastener 628, when tightened, squeezes the tether 204 between the clampbody 624 and the hasp body 626 to permanently secure the tether 604 inposition.

Referring now to FIGS. 24 and 25, correcting a spinal deformity, such asscoliosis, is described further. FIG. 24 depicts a posterior view of adeformed human spine 104 with an implanted device, and FIG. 25 depicts aposterior view of a corrected human spine 104 after the tether 204 hasbeen tensioned. As described elsewhere in this document, the implanteddevice may include two attachment mechanisms, such as pedicle screws300, which are anchored to the vertebra of the spine by insertion intoopposing pedicles, and a transverse rod 311 connected between thepedicle screws 300.

An ilium anchor 210 is attached to the ilium 102 to secure one end ofthe tether 204. The ilium anchor 210 may be in the form of a bushinginserted through a hole drilled in the ilium 102. The anchor 210 mayhave threads on its exterior surface to bite into the bone. The exteriorsurface may also include a coating of porous material, hydroxyapatite,bioconductive material, and/or bioinductive material. The tether 204 maybe passed through the anchor 210 and secured, for example, with abuckle, a loop, or other connection mechanism. The free end 206 of thetether 204 is passed through a tether clamp, for example, tether clamp320 described elsewhere herein or any other suitable tether clamp. Thetether clamp 320 may be attached to the transverse rod 311 at anysuitable location along its length. For example, the tether clamp 320may be connected to the transverse rod 311 at one end of the transverserod 311. The tether 204 may be tensioned until the deformity iscorrected as shown in FIG. 25.

The tether system may have a number of advantages. Because the tether204 connects the spine 104 to the ilium 102, the tether 204 uses thepelvis as a foundation from which to exert corrective forces onto ascoliotic spine. The tether system is not in the axial load path of thespine so forces typically borne by the spine continue to be borne by thespine. There may be no need for fusion during the life of the implant,but the system may be used prior to fusion if desired (e.g., a surgeonmay use the tether system to prevent curve progression or correct acurve and then later fuse the spine with a subsequent surgery). Theprocedure is minimally invasive and may reduce operating room timeand/or recovery time. The tether 204 is adjustable with a small incisionto accommodate progressive correction and to prevent overcorrectionduring growth modulation procedures.

Referring now to FIGS. 26 and 27, a method and device for scoliosiscorrection are shown. In particular, the device and method may includede-rotating the vertebra in the axial plane. While traditional scoliosiscorrection attempts to laterally shift the spine, this method de-rotatesthe spine because axial rotation and lateral shift are mechanicallycoupled in the thoracic spine by the ribcage. In other words, axialrotation of one or more vertebra correlates to a lateral shift in thespine and correction of the scoliotic spine. This method does not needto involve fusion to correct the spinal deformity.

As shown in FIG. 26, a non-fusion implant 700 may be used to impose ade-rotating tension on a pedicle screw 702 by using the posterior-mostaspect of the ribs 110 as an anchor point. The implantation may be aminimally invasive surgical procedure, for example, through a smallmidline incision. The implant 700 may include one or more plates 704configured to contact the ribs 110 and a pedicle screw 702 extendingthrough the plate 704. The plate 704 may be substantially straight,curved, or contoured as necessary to extend to the posterior-most aspectof the ribs 110 on either side of the vertebra 108.

The plate 704 may be implanted to abut the posterior aspect of the ribs110 on both sides of the patient. The plate 704 may be coupled to theribs 110 or may merely contact the ribs 110 without coupling thereto.The pedicle screw 702 with a threaded shank 706 may be passed through aslot 708 in the plate 704. The slot 708 may be sized to receive theshank 706 or may be elongated to allow for movement of the shank 706along the length of the plate 704. A coupling element, such as a nut710, may be used to secure the screw 702 to the plate 704. By rotatingthe nut 710 onto the threaded shank 706, the pedicle is pulled closer tothe plate 704. This action causes de-rotation of the vertebra 108 andalignment of the spine. The de-rotation can be performed acutely orprogressively over a period of time by re-accessing the nut 710 with asmall incision and adjusting at one or more different points in timeafter the initial surgery.

In another embodiment, shown in FIG. 27, instead of coupling with a nut,the threaded shank 706 may be received in a coupling sleeve 712. Thecoupling sleeve 712 may include a threaded opening extendinglongitudinally therethrough sized and dimensioned to receive thethreaded shank 706 of the screw 702. The coupling sleeve 712 may includean enlarged head portion configured to engage with the slot 708 in theplate 704. By rotating the coupling sleeve 712 onto the threaded shank706, the pedicle is once again pulled closer to the plate 704 in orderto de-rotate the vertebra 108 in the axial plane. Although depictedentering one pedicle of the vertebra 108, it is envisioned that thepedicle screw 702 could enter the opposite pedicle screw to apply torqueto the vertebra 108 in the other direction. Alternatively, if pediclescrews cannot be used, for example, in the case of a small pediatricpatient, a sublaminar band or wire can be attached to the plate 704 andtensioned as necessary to provide the desired axial movement. Regardlessof the mechanism, the axial rotation of one or more vertebrae providesfor a lateral shift in the spine and correction of the deformity.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope or spirit of the invention. Moreover,the improved bone screw assemblies and related methods of use need notfeature all of the objects, advantages, features and aspects discussedabove. Thus, for example, those skilled in the art will recognize thatthe invention can be embodied or carried out in a manner that achievesor optimizes one advantage or a group of advantages as taught hereinwithout necessarily achieving other objects or advantages as may betaught or suggested herein. In addition, while a number of variations ofthe invention have been shown and described in detail, othermodifications and methods of use, which are within the scope of thisinvention, will be readily apparent to those of skill in the art basedupon this disclosure. It is contemplated that various combinations orsubcombinations of these specific features and aspects of embodimentsmay be made and still fall within the scope of the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the discussed bone screwassemblies. Thus, it is intended that the present invention cover themodifications and variations of this invention provided that they comewithin the scope of the appended claims or their equivalents.

What is claimed is:
 1. A method of adjusting the curvature of the spinewithout fusion, the method comprising: installing an anchor into aportion of the ilium; installing two bone fasteners into the pedicles ofa vertebra and connecting an elongate rod between the two bonefasteners; attaching a first end of a tether to the anchor; attaching asecond end of the tether to a clamp, the clamp having a clamp body and ahasp body hingedly connected to the clamp body, the clamp body having afirst opening extending through the clamp body, and the hasp body havinga second opening extending through the hasp body, the clamp body furtherhaving a first elongate opening through which the second end of thetether is passed; closing the clamp such that the first and secondopenings are aligned with one another; inserting a fastener through thefirst opening in the clamp body and the second opening in the hasp bodyto securely lock the tether within the clamp; and connecting the clampto the elongate rod wherein the first elongate opening is spaced fromthe first opening such that the tether is connected to the clamp withoutcontacting the elongate rod.
 2. The method of claim 1, wherein thetether is attached to the clamp by threading the tether through thefirst elongate opening and then back through a second elongate openingextending through the clamp body to temporarily hold the tether in theclamp.
 3. The method of claim 1, further comprising tensioning thetether in order to modify the curvature of the spine.
 4. The method ofclaim 1, wherein the elongate rod extends laterally across the spinalcolumn.
 5. The method of claim 1, wherein the anchor includes a bore andthreading on an outer surface to allow the anchor to be threaded intothe portion of the ilium.
 6. The method of claim 5, wherein the bore ofthe anchor is configured and dimensioned to receive the first end of thetether.
 7. The method of claim 1, wherein the tether is flexible.
 8. Themethod of claim 1, wherein the clamp body has a second elongate openingsuch that the first elongate opening is disposed between the firstopening of the clamp body and the second elongate opening, wherein thestep of attaching a second end of the tether to a clamp includes:passing the second end of the tether through the first elongate openingin the clamp body and back through the second elongate opening such thatthe tether folds back onto itself.
 9. The method of claim 8, wherein thestep of connecting the clamp to the elongate rod compresses the tetherbetween the hasp body and the clamp body.
 10. The method of claim 8,further comprising adjusting the tension of the tether after passing thesecond end of the tether through the first elongate opening in the clampbody and back through the second elongate opening, and before the stepof connecting the clamp to the elongate rod.
 11. The method of claim 1,wherein the step of connecting the clamp to the elongate rod includestightening the fastener to squeeze the tether between the clamp body andthe hasp body.
 12. The method of claim 1, wherein the elongate rodincludes a clamp hole and the step of inserting a fastener includesinserting the fastener through the first opening in the clamp body, thesecond opening in the hasp body and the clamp hole of the elongate rod.13. The method of claim 1, wherein the elongate rod includes a clamphole and the step of inserting a fastener includes inserting thefastener through the second opening in the hasp body and then the firstopening in the clamp body, and then the clamp hole of the elongate rod.